Half a century later it has become such a vital service that the branch was contacted 56,000 times in 2013 by people who needed a listening ear.

The charity celebrated its 50th anniversary with a special event and open day yesterday, with bosses estimating that it has been contacted more than a million times since it was first formed.

Director David Saunders said most people continued to contact them by telephone, but emails and texts were increasing, and 90pc of those texting were under the age of 25.

In 2013 the centre also hosted 407 face-to-face sessions at its St Stephens’ Square centre, which was bought by the charity when it first formed and where it has been based ever since.

The sheer dedication of the charity’s volunteers means it is the only branch in the eastern region to remain open 24 hours a day, seven days a week – a feat which it has managed to maintain throughout its impressive five decades.

Mr Saunders paid tribute to the hard work and dedication of the charity’s 170 listening volunteers and another 30 volunteers who help by running the branch or by manning its charity shops in Aylsham Road and Westlegate.

He said: “I tried to work out how many volunteering hours had been given to Norwich Samaritans in the last 50 years and came to a figure of over two million hours. The charity shops keep us going because it costs about £80,000 a year to keep our branch open.

“Without the shops and all our volunteers we would really struggle to keep going 24 hours a day.”

The charity supports two prisons, Norwich and Bure, by training prisoners to become listeners who can offer support to fellow inmates.

Norwich Samaritans also works with schools, offering support for pupils and teachers following a suicide, and free sessions for schools in the Norwich area to talk to young people about emotional health, peer pressure, self-harm and how to identify when someone needs help and how to help them.

Volunteer Michael (volunteers do not use their surnames) called the charity for support when his marriage broke down. He never forgot how the volunteer he spoke to helped him through a difficult time and, years later, he decided he wanted to help people in the same way.

He said: “It can be very satisfying if you feel that you have been helpful to somebody.”

Jean first got involved as a volunteer after her youngest daughter went to university and she felt she had a lot of spare time on her hands.

As the person to whom friends and family turned with their worries, she said it seemed a natural step for her to offer a listening ear to strangers and she has now been with the Samaritans for 18 years. She said: “It seems a strange thing to do, listening to other people’s problems, but it gives us a feeling of self worth because we are helping people.”

The Samaritans can be contacted on 08457 909090 or by email at jo@samaritans.org. People can also drop-in in person, between 8am and 9.30pm, at 19 St Stephen’s Square, Norwich.